1. Field of the Invention
The present invention relates to an air bag apparatus installed in an instrument panel of a vehicle such as an automobile to protect a passenger, a method of folding an air bag of the air bag apparatus, and a method of deploying the air bag.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. HEI 6-127320 and Japanese Patent Application Laid-Open No. HEI 6-191362 disclose air bag apparatus for a passenger seat.
HEI 6-127320 discloses an air bag having an opening portion, a winding portion adjacent to the opening portion, and a folded portion adjacent to the winding portion and folded into a predetermined shape. The opening portion of the air bag is attached to a case. The folded portion is wound by the winding portion counterclockwise as viewed from the right side of the vehicle so as to be accommodated in the case. The thus-constructed air bag apparatus ensures that upon activation of an inflator, the air bag is first deployed upwards along a wind shield and then rearwards and downwards so as to attenuate an impact made on a passenger.
HEI 6-191362 discloses an air bag arrangement in which an inflator is disposed within a case at a location biased toward a bottom wall and a front wall of the case. The inflator has two gas ejection ports formed in an outer periphery thereof, and those gas ejection ports are opposed to each other. The gas ejected from one of the gas ejection ports moves diagonally upwards from the front wall side of the case, whereas the gas ejected from the other gas ejection port moves diagonally downwards from the rear wall side of the case. An air bag in its folded state is accommodated between the inflator and the rear wall of the case. The thus-constructed air bag apparatus, upon activation of the inflator, will deploy upper and lower portions of the air bag upwards and downwards, respectively earlier than a central portion thereof, whereby the air bag assumes its ultimate shape relatively early in the process of deployment.
However, these air bag apparatus encounter the following problems.
In the HEI 6-127320 arrangement, upon activation of the inflator, the folded portion of the air bag pops out of the case without being unfolded and deployed upwards. If the folded portion comes into contact with a passenger while the air bag is still being deployed, the folded portion rubs against the passenger in accordance with a deployment process of the folded portion.
In the HEI 6-191362 arrangement, upon activation of the inflator, the upper and lower portions of the air bag are deployed while the central portion thereof remains as it is. If a wrinkled central rear face portion of the air bag comes into contact with the passenger while the air bag is still being deployed, the air bag also rubs against the passenger.